In the present urban parking systems in use in North America, parking is paid for on most urban streets and many city lots by inserting coins into a parking meter assigned to each parking space. A parking warden or checker periodically checks each parking meter and each corresponding parking space to determine if a citation should be written up.
For the motorist, the convenience of being able to pay at the curb and then be on one's way is of great importance.
It is known in the art from U.S. Pat. No. 4,812,805 to LaChat et al. and U.S. Pat. No. 4,876,540 to Berthon et al. to provide portable terminals which receive vehicle parking status data pairs (i.e. vehicle ID number and expiration time) from curbside payment terminals, and to provide a low energy consumption data communication system among the payment terminals. Such an electronic urban parking system is able to comply with the basic requirements for an efficient system, namely, the motorists may pay at a curbside payment terminal and may then be free to go without returning to their vehicle to place a proof of payment instrument, and the portable terminals may be provided with sufficiently accurate data to determine with reasonable accuracy whether a vehicle's parking is paid for.
However, in larger urban areas, Applicants have determined that a large number of payment terminals are required for motorists' convenience, especially when harsh climate conditions of cold, heat and precipitation are common. Motorists may, for convenience, wish to pay for parking indoors or at a payment terminal not immediately associated with the parking space occupied. Since payment may take place far away from the parking space, it is no longer sufficient for a parking warden to acquire local information from neighboring curbside payment terminals. For these reasons, it is desirable to make large areas, such as entire business districts, into individual parking zones and permit payment of parking from any terminal in the zone, or even from outside the zone. To accommodate such marketing, a large number of payment terminals needs to provide data to a large number of portable terminals and at longer distances.
Under such circumstances, the amount of vehicle data received from the payment terminals and transferred to portable checking terminals requires special consideration for efficient handling. It has been determined that the known handling of parking data, i.e. either transmission from the payment terminal periodically to an individual portable terminal or transmission from the payment terminal upon request to the requesting portable terminal, cannot efficiently handle the required large amount of data transfer when a large number of payment terminals are used and when parking zones encompass a number of payment terminals. In addition, data transferred locally from a payment terminal to portable terminals periodically and upon request is neither complete nor up to date when motorists are allowed to park anywhere within a zone including many payment terminals.